The traditional mold centering system comprises two portions, a male portion and a female portion, made in steel and having diverse material hardness, so a greater adjustment can be achieved with greater friction without any sliding problem whatsoever, in such a way that usually it is provided with graphite pads that act as a solid lubricant element, and even different coverings on the female portion to smooth the friction.
Mainly, there are two models, which differ in the way of attaching the moving panels of the mold and this attachment method determines the movement length or adjustment. The top attachment movement to the panel has a limited travel and the lateral attachment movement to the panel can have a larger travel and without limit, depending on the length of the male component.
Based on the top attachment model with a limited travel, a traditional mold centering system has a cage that supports a set of rollers between the male and the female portions, so that a greater adjustment between both of them can be achieved due to the friction reduction, since there is not friction against the walls but against the rollers, which have a rotating motion but not a translation one. The roller cage has also a specific length, which conditions the adjustment length. It also should be noted that there is friction between the male element and the female element.